Washington: Female sexual dysfunction (FSD), a condition that may range from a lack of libido to an inability to achieve orgasm, affects 40 to 45 per cent of women, especially as they age.

FSD can be tough to diagnose and even more difficult to treat. And while clinicians have attempted to help women by prescribing sildenafil (better known by its brand name, Viagra), hormones, and flibanserin, these methods don't always work and can have undesirable side effects.

This is why researchers were intrigued after learning that neuromodulation treatments for bladder dysfunction occasionally led to improvements in sexual function.

Tim Bruns, one of the head researchers said, "In this particular treatment, a patient receives nerve stimulation therapy once a week to improve neural signalling and function in the muscles that control the bladder. The nerves controlling the pelvic organs start out in the same location in the spinal cord and branch out."

Interestingly, Bruns notes, one form of stimulation is effective for bladder dysfunction despite an odd placement of the electrodes: near the tibial nerve in the ankle.

According to the current theory, that the nerves that travel down to the foot overlap near the spinal cord with some of the nerves to the pelvic organs, leading to a possible overlap in synaptic routes. Bruns decided to study the technique in rats and humans.

In the rat studies published last year and earlier this year, Bruns' team stimulated nerves in the genital and ankle region. After 15 to 30 minutes, the rodents experienced a strong increase in vaginal blood flow.

For the following study, researchers recruited nine women with FSD (and without bladder problems) for a pilot study. Each woman received 12 half-hour sessions of transcutaneous electrical nerve stimulation in which participants had electrodes placed either in the genital region or on the ankle.

A 53-year-old woman who got involved with the study after reporting difficulty achieving orgasm to her gynaecologist described the experience as "a bizarre, pressure vibration sensation." She later added that "After a few minutes, however, you get used to it. You sit there for 30 minutes. I brought a book to read during my session."

Results of the sessions showed substantial promise. Eight out of the nine women reported some improvement in arousal, lubrication and orgasm.

"Across a variety of clinical studies, if you get a 50 per cent improvement in symptoms, you can consider that a successful response," Bruns says. "We had four participants meet or exceed that threshold."

Overall improvement in score was comparable or greater than prior studies of different types of drugs or neuromodulation for FSD, he adds. However, future studies with blinding and a placebo control are needed to rule out any placebo effect.